Carpet Inspection

Carpet inspection mainly conducts scientific testing and analysis on physical property testing, colour fastness testing, flame retardancy testing, hazardous substance limit testing, appearance retention testing and mechanical property testing, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Physical property testing: Mainly including the tests of the abrasion resistance, thickness, density and mass per unit area. For the abrasion resistance, the standard such as ISO 12947 is usually followed, using a Martindale abrasion tester to simulate long-term trampling and evaluate the loss of the fibres on the carpet surface. The thickness and density directly affect the foot feel, resilience and durability of the carpet, and are the basic indicators for evaluating its quality grade.

Colour fastness testing: Evaluates the stability of the carpet colour in various environments. The key items include the colour fastness to light (simulating light fading), colour fastness to rubbing (dry and wet rubbing), colour fastness to water spotting and colour fastness to cleaning agents. These tests are crucial for ensuring that the carpet does not severely fade or stain under cleaning, sunlight exposure or humid conditions.

Flame retardancy testing: This is the core testing item involving safety. The common methods include the vertical burning test, the tablet test (such as GB/T 14768) and the radiant panel test. The report needs to clearly record the burning time, damaged length, and whether there is afterflame and afterglow of the specimen, to judge whether it meets the fire safety codes of specific places (such as aviation, ships and high-rise buildings).

Hazardous substance limit testing: Quantitative analysis is carried out on the chemical hazards that may exist in the carpet. The main testing items include the total volatile organic compounds (TVOC), formaldehyde release amount, extractable heavy metals (such as lead, cadmium, chromium and mercury) and the content of specific azo dyes, ensuring that the product meets the mandatory national standards such as GB 18587 "Indoor decorating and refurbishing materials — Limit of harmful substances of carpets, carpet pads and carpet adhesives".

Appearance retention testing: Evaluates the resistance of the carpet to appearance changes after a period of use. It mainly includes the pile retention (anti-lay-flat), antistatic property, stain resistance and cleanability testing. For example, the indentation recovery ability of the carpet is evaluated through the castor chair test, which is one of the key indicators for evaluating the performance of commercial carpets.

Mechanical property testing: Evaluates the structural integrity of the carpet under force. It includes the tensile breaking strength and elongation at break, the back coating peeling strength and the dimensional stability (dimensional change after dry heat or water immersion). These data are directly related to the installation firmness, the deformation control during use and the service life of the carpet.

Testing Scope

Tufted carpets: Carpets formed by puncturing yarns into the backing fabric with a tufting machine to form loop pile or cut pile. Testing needs to focus on the pile height, tuft withdrawal force, coating application uniformity and peeling strength. Its scope of application is wide, covering home bedrooms, hotel corridors and medium and low load commercial spaces.

Woven Wilton carpets: Traditional high-grade carpets woven by the Wilton loom with warp yarns, weft yarns and pile yarns interwoven. Testing focuses on the pattern definition, colour interweaving accuracy, dimensional stability at high density and the strength of the complex back coating structure. They are commonly found in high-end hotels, meeting rooms and other places that emphasize patterns and durability.

Woven Axminster carpets: Produced by the Axminster loom, with rich patterns and independently configurable pile. The testing scope includes the colour fastness of complex patterns, the dyeing uniformity of yarns of different colours, the pile height consistency and the dimensional change rate caused by its special structure.

Needle-punched carpets: Nonwoven carpets formed by consolidating the fibre web into a felt-like structure through the needle-punching process. The testing focus is on the uniformity of the fibre web, delamination resistance, abrasion resistance (usually lower) and the compression resilience and creep performance when it is often used as a carpet underlay.

Modular carpet tiles: Modular carpets usually made by the tufting or needle-punching process. In addition to the conventional items, the dimensional tolerances, squareness, edge straightness and the flatness and colour difference after splicing need to be specially tested, which have a decisive influence on the visual effect and construction quality of large-scale installation.

Carpet matching materials: The testing scope is not limited to the carpet surface layer, but also includes the carpet underlays (sponge, rubber and fibre) and adhesives used with it. The density, compression set and formaldehyde release of the underlay, and the bonding strength, TVOC and other indicators of the adhesive need to be independently tested and evaluated.

Testing Methods and Standards

Abrasion resistance testing (Martindale method): In accordance with the ISO 12947 or GB/T 13775 standard series. The circular specimen is subjected to Lissajous figure trajectory friction with a standard abrasive under a specified pressure, and the number of frictions when obvious wear or yarn breakage appears is recorded. This method can effectively simulate the long-term friction of shoe soles and chair legs on the carpet, and is the core method for evaluating the durability grade of the carpet.

Colour fastness test methods: The colour fastness to rubbing is in accordance with GB/T 3920, using dry/wet standard white cloths on a rubbing testing machine; the colour fastness to light is in accordance with GB/T 8427, using a xenon arc lamp fading machine to simulate sunlight exposure; the colour fastness to water spotting and cleaning agents is respectively in accordance with GB/T 5713 and GB/T 5714, assessing the change in colour of the specimen and the staining grade of the adjacent fabric after immersion, pressing and drying.

Flame retardancy test methods: The vertical burning method commonly uses GB/T 5455, measuring the burning behaviour of the specimen after contact with a flame in a vertical state. The tablet method (such as GB/T 14768) simulates the influence of small flame sources such as lit cigarettes on the carpet. The radiant panel method (such as ASTM E648) tests the critical radiant flux of the carpet, and is a high-standard method for evaluating the resistance of floor coverings to flame spread.

Hazardous substance test methods: The TVOC and formaldehyde release are usually determined by the climate chamber method (Annex A of GB 18587), collecting and analysing the gas under the specified temperature, humidity and air exchange rate. The extractable heavy metals are determined in accordance with GB/T 30157, extracting with an acid perspiration simulation solution and then determining with instruments such as inductively coupled plasma spectroscopy (ICP). The azo dyes are detected in accordance with GB/T 17592.

Static property testing: Usually in accordance with GB/T 18044 (walking method) or ASTM D3676 (walking test). The testers wearing standard shoes walk on the carpet under specific temperature and humidity conditions, measuring the generated static voltage peak and half-life, to evaluate the risk of static generation of the carpet in dry environments.

Appearance change evaluation method: The castor chair test is in accordance with ISO 4918, simulating the indentation caused by the movement of office chairs with castors on the carpet, and evaluating its recovery. The pile retention can be assessed by comparing the difference between the trampled area and the untrampled area through visual comparison or with a gloss meter.

Testing Standards

Domestic Standards:

1. GB 18587, Indoor decorating and refurbishing materials — Limit of harmful substances of carpets, carpet pads and carpet adhesives

2. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

3. GB/T 8427-2019, Textiles — Tests for colour fastness — Colour fastness to artificial light: Xenon arc fading lamp test

4. GB/T 5455-2014, Textiles — Burning behaviour — Determination of damaged length, afterglow time and afterflame time

5. GB/T 30157, Textiles — Determination of phthalates

International Standards:

1. ISO 12947, Textiles — Determination of the abrasion resistance of fabrics by the Martindale method

2. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

3. ISO 105, Textiles — Tests for colour fastness

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Martindale abrasion and pilling tester: This equipment is the key instrument for evaluating the abrasion resistance of carpets. A standard pressure is applied to the specimen through replaceable loads and mass blocks, and the abrasion table is driven to carry out trajectory friction. The instrument is equipped with an electronic counter, precisely recording the number of frictions until the preset termination point is reached or specimen damage is observed.

Xenon arc lamp light fastness testing machine: Used to simulate and accelerate the influence of natural sunlight on the carpet colour. The equipment controls the spectral energy distribution of the xenon arc lamp through a filter system, precisely controls the chamber temperature, humidity and black panel temperature, and can carry out dark cycle cycles according to the standard requirements, to comprehensively evaluate the light aging performance of the carpet.

Vertical burning tester: Used to determine the flame retardant characteristics of the carpet. The instrument is equipped with a standard burner, specimen holder, timer and marking lines. During the test, the specimen is vertically hung, a specified flame is applied for a certain time and then removed, and the afterflame time and afterglow time are automatically recorded, and the damaged length is measured.

Climate chamber and gas chromatography-mass spectrometer: The climate chamber is used to provide a stable and controllable temperature, humidity and air exchange rate environment, so that the volatile substances in the carpet sample are stably released. The released gas is collected and then analysed qualitatively and quantitatively with a thermal desorption instrument combined with GC-MS, precisely detecting formaldehyde, TVOC and various characteristic hazardous organic substances.

Universal material testing machine: Used for the mechanical property tests of the carpet such as tensile, peeling and bursting. Equipped with different grips (such as tensile grips and peeling grips), it can set parameters such as the tensile speed and sampling frequency according to the standards, automatically record the force-displacement curve, and calculate key data such as the breaking strength, elongation at break and peeling strength.

Static decay tester: Used to measure the static property of the carpet. The equipment usually includes a high-voltage discharge probe and a field meter or induction probe. First, the surface of the specimen is charged to a high voltage, then the high voltage is cut off and the time required for the surface voltage to decay to half of the initial value (half-life) is automatically recorded, thereby evaluating the static dissipation ability of the material.